Variable device for bulk material distribution with rotary chute having variable angle of inclination

ABSTRACT

The invention concerns a device for distributing bilk material comprising: a tilting chute ( 32 ) suspended to a suspension rotor ( 18 ) driven in rotation by a motor ( 60 ); a tilt controlling rotor ( 28 ) and a tilting mechanism ( 36, 36′ ), which transforms a differential rotation of the two rotors ( 18, 28 ) into a tilting motion of the chute ( 32 ). A first braking mechanism ( 80 ) is associated with the tilt controlling rotor ( 28 ) and a first control device ( 102, 106 ) controls the variation of the angle of inclination of the chute  832 ) by controlled braking of the tilt controlling rotor ( 28 ).

FIELD OF THE INVENTION

[0001] The present invention relates to a device for distributing bulkmaterials with a rotary chute with a variable angle of inclination.

[0002] More specifically, it relates to such a device comprising asupport frame, a chute for distributing bulk materials, a suspensionrotor and a tilt controlling rotor, as well as a tilting mechanism. Thechute is suspended to the suspension rotor so as to be tiltable about asubstantially horizontal tilt axis. The tilting mechanism is connectedbetween the chute and the tilt controlling rotor in order to transform adifferential rotation of the suspension rotor and of the tiltcontrolling rotor into a variation of the angle of inclination of thechute between two extreme positions.

BACKGROUND OF THE INVENTION

[0003] Such a device is known for example from U.S. Pat. No. 3,693,812.In this device, both rotors are rotated via a planetary gear box. Fromthis planetary gear box, emerge: (1) a main input shaft; (2) a secondaryinput shaft; (3) a first output shaft, called rotary shaft hereafter;and (4) a second output shaft, called tilt controlling shaft hereafter.The main input shaft is rotated by a driving motor. A demultiplyingmechanism connects the main input shaft to the rotary shaft. The latterpenetrates into the support frame where it engages by means of a pinionwith a toothed ring of the suspension rotor. The tilt controlling shaftitself also penetrates into the support frame, where it engages by meansof a pinion with a toothed ring of the tilt controlling rotor. Theplanetary gear box further comprises: a horizontal annular toothedwheel, which engages at its external perimeter with a pinion of therotary shaft; a solar wheel which is borne by the secondary input shaft;at least two satellite pinions, which engage with the internal perimeterof the annular toothed wheel and the solar wheel; and a satellite pinioncarrier, which engages with a toothed wheel of the tilt controllingshaft. These gears are dimensioned so that both output shafts have thesame speed of rotation when the secondary input shaft is not rotating. Acontrol motor with a reversible direction of rotation is connected tothe secondary input shaft of the planetary gear. By driving this controlmotor in a first direction, the chute is tilted in a first direction andby driving it in the reverse direction, the chute is tilted in thereverse direction. The speed of rotation of the control motor determinesthe tilt speed of the chute, regardless of the speed of rotation of thechute. By blocking the secondary input shaft by means of a brake, astrictly constant angle of inclination is provided for the rotatingchute.

[0004] It will be noted that this planetary gear box is a key piece ofequipment of the device for distributing bulk materials. This is aspecial design which accounts for a large portion of the price of thedevice. Further, in order to remain operational when the driving unitrequires servicing or a major repair, a complete planetary gear boxshould be kept in reserve.

OBJECT OF THE INVENTION

[0005] The object of the present invention is to provide a device fordistributing bulk materials of the type described above, with a simplerdriving mechanism, notably causing less problems in the case of majorservicing or repairs.

SUMMARY OF THE INVENTION

[0006] According to the invention, this object is achieved by a devicefor distributing bulk materials comprising—in a known way per se—asupport frame, a chute for distributing the bulk materials, a suspensionrotor, a tilt controlling rotor and a tilting mechanism. Both rotors aremounted on the support frame so that they are both capable of rotatingabout a substantially vertical axis of rotation. The chute is suspendedto the suspension rotor, so as to be tiltable about a substantiallyhorizontal tilting axis. The suspension rotor (and consequently thechute) can be driven with a first motor in a first direction about itsaxis of rotation. The tilting mechanism is connected between the chuteand the tilt controlling rotor, in order to transform a differentialrotation of the suspension rotor and of the tilt controlling rotor intoa variation of the angle of inclination of the chute between two extremepositions. According to a first aspect of the present invention, thechute is balanced in order to return to a first of its two extremepositions, while accelerating the tilt controlling rotor via the tiltingmechanism in the direction of rotation of the suspension rotor. In thisembodiment, a first braking device is associated with the tiltcontrolling rotor so that it is capable of exerting a braking moment onthe tilt controlling rotor. With this first braking device is associateda first control device which allows the tilting of the chute to becontrolled by controlling the braking moment applied to the tiltcontrolling rotor, when the suspension rotor is driven in the firstdirection of rotation. If the braking moment exerted on the tiltcontrolling rotor is equal to the moment required for maintaining thechute in an equilibrium position, the chute remains fixed in tilt. Ifthe braking moment exerted on the tilt controlling rotor is larger thanthe moment required for maintaining the chute in the equilibriumposition, the chute moves away from its first extreme position ofinclination. If the braking motor exerted by the tilt controlling rotoris less than the moment required for maintaining the chute in theequilibrium position, the chute moves closer to its first extremeposition of inclination, because its special balancing causes anacceleration of the tilt controlling rotor relatively to the suspensionrotor. In the three cases, the first motor must of course develop adriving moment which is larger than the braking moment of the tiltcontrolling rotor, while providing a substantially constant speed ofrotation. It remains to be noted that for providing the balance of thechute which ensures its return to a first of its two extreme positions,it is possible to either involve the weight of the chute exclusively orresort to counterweights or springs or other components capable ofstoring potential energy when the chute is tilted in one direction andof releasing it when the chute should be tilted in the reversedirection. As a conclusion, by associating the tilt controlling rotorwith a simple braking device having a controllable braking moment, theangle of inclination of the chute as well as its tilting speed can becontrolled, when the latter rotates in a first direction.

[0007] In order to provide rotation of the chute with a strictlyconstant angle of inclination without having to continually brake thetilt controlling rotor, a clutch transmission mechanism can be connectedbetween the suspension rotor and the tilt controlling rotor. In theengaged position, this mechanism makes both rotors interdependent inrotation, i.e. provides a same speed or rotation for both rotors,whereas in the disengaged position of the clutch, the mechanism providesacceleration, deceleration of one rotor relatively to the other,respectively. In other words, after having set a particular angle ofinclination of the chute by varying the braking moment of the tiltcontrolling rotor with the transmission mechanism disengaged, thetransmission mechanism can be engaged in order to mechanically set theangular shift of both rotors and thus provide a strictly constant angleof inclination of the chute without having to spend any energy for thispurpose.

[0008] If the intention is not to be limited to one direction ofrotation for the chute or to be able to adjust the angle of inclinationof the chute when the latter is rotationally fixed, a second motor mustbe associated with the tilt controlling rotor so as to be capable ofdriving the latter about its axis of rotation in a second direction ofrotation, and a second braking device must be associated with thesuspension rotor so that as to be capable of exerting a braking momenton the suspension rotor. A control device which is associated with thesecond braking device, provides in this case control over the variationof the angle of inclination of the chute rotating in the seconddirection, by changing the braking moment of the suspension rotor. Inorder to provide a strictly constant angle of inclination of the chutewithout having to spend energy for this purpose, one will advantageouslyresort to the gear transmission mechanism described earlier. It remainsto be noted that the inclination of the chute may also be changedwithout driving it into rotation. For this purpose, the suspension rotoris blocked in rotation via the second braking device and the tilt of thechute is controlled in a first direction by having the tilt controllingrotor driven by the second motor and in a second direction by brakingthe tilt controlling rotor via the first braking device, takingadvantage of the fact that the balance of the chute makes it return to afirst of two extreme positions.

[0009] In order to guarantee a substantially constant speed of rotationof the chute in said second direction of rotation, when the angle ofinclination of the chute is varied by braking the suspension rotor, avariable speed drive must be associated with the second motor. With acontrol device associated with the variable speed drive, the desiredspeed of rotation of the suspension rotor may then be provided, whereaswith the second control device controlling the braking moment of thesuspension rotor, the desired tilting speed of the chute can beprovided. Alternatively, the speed of rotation of the chute can beimposed via the second braking device and a control device can beassociated with the variable speed drive of the second motor, andprovide direct control over the tilting speed of the chute. It remainsto be noted that in both cases, the second motor with its variable speeddrive should be able to drive the tilt controlling rotor at a speed ofrotation higher and less than the desired speed of rotation for thechute.

[0010] In the above description, it is assumed that the chute isbalanced so that it returns to a first of its two extreme positions,while accelerating the tilt controlling rotor via the tilting mechanismin the direction of rotation of the suspension rotor. If such balancingwere not possible, the device according to the invention should beequipped as follows. A first braking device is associated to the tiltcontrolling rotor so that it is capable of exerting a braking moment onthe tilt controlling rotor. A second motor is associated with the tiltcontrolling rotor, so that it is capable of driving the latter about itsaxis in the first direction at a higher speed of rotation than thedesired speed of rotation for the chute. A second braking device isassociated with the suspension rotor so that it is capable of exerting abraking moment on the suspension rotor. A control device then allows thetilting of the chute to be controlled in a first direction, by drivingthe suspension rotor in the first direction and by controlled braking ofthe tilt controlling rotor by means of the first braking device, and ina second direction, by driving the tilt controlling rotor in the firstdirection, at a higher speed of rotation than the desired speed ofrotation for the chute, and by controlled braking of the suspensionrotor by means of the second braking device.

[0011] If, in the device of the above paragraph, the tilting mechanismis a perfectly self-blocking mechanism, i.e. no moment needs to beapplied to said tilt controlling rotor in order to maintain the chutefixed in tilt, then it is sufficient to rotate the suspension rotor andnot to brake the tilt controlling rotor in order to provide rotation ofthe chute with a strictly constant angle of inclination. If however thetilting mechanism is not perfectly self-blocking or if there is a riskthat wear and tear will destroy its self-blocking character, it is thenrecommended to equip the device with a transmission mechanism having aclutch as described earlier.

[0012] If the intention is not to be limited to only one direction ofrotation for the chute, the first motor needs to be able to drive thesuspension rotor in a second direction of rotation at the desired speedof rotation for the chute, and the second motor should be able to drivethe tilt controlling rotor in the second direction of rotation at ahigher speed of rotation than the desired speed of rotation for thechute. In this case, the control device associated with the firstbraking device, with the second braking device and with the secondmotor, must be able to control the tilting of the chute: (a) in a firstdirection, by driving the tilt controlling rotor by means of the secondmotor in the second direction at a higher speed of rotation than thedesired speed of rotation for the chute and by controlled braking of thesuspension rotor by means of the second braking device; and (b) in asecond direction, by driving the suspension rotor in the seconddirection and by controlled braking of the tilt controlling rotor bymeans of the first braking device. It remains to be noted that in thisdevice, the inclination of the chute may also be changed without drivingit into rotation. For this purpose, the rotating suspension rotor isblocked via the second braking device and the tilt of the chute iscontrolled, in a first direction, by having the tilt controlling rotordriven by the second motor in a first direction, in a second direction,by having the tilt controlling rotor driven by the second motor in asecond direction.

[0013] In order to guarantee with the device described in the aboveparagraph, a substantially constant speed of rotation of the chute whenthe angle of inclination is varied by braking the suspension rotor, avariable speed drive should be associated with the second motor. Acontrol device associated with the variable speed drive is then able toprovide the desired speed of rotation of the suspension rotor, whereasthe second control device controlling the braking moment of thesuspension rotor, is able to provide the desired tilting speed of thechute. Alternatively, the speed of rotation of the chute can be imposedvia the second braking device and a control device can be associatedwith the variable speed drive of the second motor, and then providedirect control over the tilting speed of the chute. It remains to benoted that the second motor with its variable speed drive, needs to beable to drive the tilt controlling rotor at a higher speed of rotationthan the desired speed of rotation for the chute.

[0014] It is important to note that the braking device used in a devicesuch as the one described above, for braking the tilt controlling rotoror the suspension rotor may for example be a mechanical, hydraulic,magnetic or electromagnetic brake. In a preferred embodiment of a deviceaccording to the invention, the first motor and the second, brakingdevice, the second motor and the first braking device respectively,however form a unit comprising a rotating electric machine powered by anelectrical circuit so that it is capable of operating in motor mode todevelop a driving torque and in a generator mode to develop a brakingtorque, this in at least one direction of rotation. In other words, thefirst driving motor, the second driving motor respectively, alsofulfills the function of an electric brake. It remains to be noted thatthis solution not only simplifies the construction of the device (noneed to provide a separate brake) but it is also of interest from thepoint of view of the energy balance of the device. Indeed, the rotatingelectric machine operating in generator mode transforms braking powerinto electrical power, which it injects into the mains electric powersupply network. This electrical power is then used for at least partlycompensating the electrical power that the rotating electric machineoperating in the motor mode absorbs in order to overcome the brakingmoment developed for controlling the angle of inclination of the chute.

[0015] In a preferred embodiment of a device according to the invention,the rotating electric machine is for example an electric motor equippedwith a speed reducer, and the electrical circuit is a static frequencyconverter. These are standard cheap pieces of equipment and theirreplacement in the event of machine breakage will normally not be aproblem.

[0016] It remains to be noted that the devices for controlling the tiltof the chute as mentioned above, may comprise different means forsensing the inclination of the chute. In a first embodiment, a firstangle sensor is used which senses the angular position of the suspensionrotor, a second angle sensor sensing the angular position of the tiltcontrolling rotor and computation means for computing the relativeangular position of both rotors, and for inferring therefrom the tilt ofthe chute. However, better accuracy of the control device is providedwhen a differential angle sensor is used which directly senses therelative angular position of both motors. This accuracy may further beenhanced by connecting a differential measurement mechanism between bothmotors. Such a mechanism comprises e.g. a first input shaft, a secondinput shaft and an output shaft. The first input shaft is rotated by thesuspension rotor and the second input shaft is rotated by the tiltcontrolling rotor. This differential measurement mechanism isdimensioned so that the output shaft is rotationally fixed when bothrotors have the same speed of rotation and so that it reproduces theangle of inclination of the chute in a rotationally fixed referencesystem. A single angle sensor then senses the angular position of theoutput shaft of the differential measurement mechanism and thus detectsthe inclination of the chute in a rotationally fixed reference system.The tilt controlling device may also comprise a sensor for theinclination of the chute, rotating with the chute. In this case, atransmitter is associated with the rotationally mobile inclinationsensor and at least one receiver is mounted in the rotationally fixedsupport frame. In this way, it is known how to measure the tilt of thechute directly in its rotating referential.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features and characteristics of the invention will becomeapparent from the detailed description of a few advantageous embodimentsshown below, by way of illustration, with reference to the appendeddrawings:

[0018]FIG. 1 shows a planar view of a device for distributing bulkmaterials with a rotary chute having a variable angle of inclinationaccording to the invention;

[0019]FIG. 2 shows a longitudinal sectional view through the device ofFIG. 1, the upper portion being a sectional view along the sectionalline A-A of FIG. 1; the lower portion being a sectional view along thesectional line B-B of FIG. 1;

[0020]FIG. 3 is an elevational view of a detail which is identified byarrow 3 in FIG. 2;

[0021]FIG. 4 is a longitudinal sectional view similar to that of FIG. 2,through a first alternative embodiment of a device for distributing bulkmaterials with a rotary chute having a variable angle of inclinationaccording to the invention;

[0022]FIG. 5 is a longitudinal sectional view similar to that of FIG. 2,through a second alternative embodiment of a device for distributingbulk materials with a rotary chute having a variable angle ofinclination according to the invention; and

[0023]FIG. 6 is a transverse sectional view, the sectional line of whichis identified by arrows 6-6 in FIG. 5.

DETAILED DESCRIPTION OF A FEW ADVANTAGEOUS EMBODIMENTS OF THE INVENTION

[0024] In the figures, the same reference symbols refer to identical orsimilar components.

[0025] The device for distributing bulk materials 10 shown in FIGS. 1,2, 4 and 5, is more particularly intended to be part of a chargingdevice of a shaft furnace, such as a blast furnace for example. Itcomprises an external frame 12, which is provided with a fixed feedingsleeve 14 defining a vertical feeding channel 16. A suspension rotor 18is suspended in the external frame 12 by means of a large diameter ballbearing 20. This suspension rotor 18 comprises a cylindrical bodyprovided at its lower end with a horizontal flange 24, which acts as ascreen between the inside of the frame 12 and the inside of the furnace.A second rotor 28, called the tilt controlling rotor 28, surrounds thesuspension rotor 18 and is suspended in the external frame 12 by meansof a large diameter ball bearing 26, in order to have its axis ofrotation substantially coaxial to the axis of rotation of the suspensionrotor 18.

[0026] Reference symbol 32 refers to a distribution chute for bulkmaterials poured in through the feeding channel 16. This chute 32comprises two side suspension arms 34 and 34′, by means of which it issuspended to the suspension rotor 18. With a tilting mechanism actuatedby the tilt controlling rotor 28, the chute 32 can be tilted about asubstantially horizontal tilt axis. In the illustrated device, thistilting mechanism comprises per suspension arm 34, 34′ of the chute 32,a suspension mechanism 36, 36′ borne by the suspension rotor 20. Each ofboth of these suspension mechanisms 36, 36′, comprises a vertical inputshaft 38, 38′, an internal gear system (not shown) and a horizontalsuspension pin 40,40′. Both side suspension arms 34, 34′ of the chute32.are coupled with suspension pins 40,40′ and the latter define asubstantially horizontal tilt axis for the chute 32. The vertical inputshaft 38, 38′ of each of both suspension mechanisms 36, 36′ is equippedwith a pinion which engages with a toothed crown 43 of the tiltcontrolling rotor 28. The internal gear system transforms a rotation ofthe vertical input shaft 38, 38′ into a rotation of the suspension pin40,40′. It will be noted that both suspension mechanisms 36 and 36′should be symmetrical with respect to the middle plane of the chute 32,i.e. a rotation in the same direction as the input shaft 38, 38′, shouldresult in a rotation in opposite directions of both suspension pins40,40′.

[0027] It is important to note that other tilting mechanisms connectedto the chute and actuated by the tilt controlling rotor are also known.Thus, U.S. Pat. No. 4,941,792 for example proposes the use as a tiltingmechanism, respectively of a forked tilting lever connected between bothpins and the tilt controlling rotor, or of a toothed ring segment whichcooperates with a toothed sector interdependent with one of both of thepins of the chute. U.S. Pat. No. 5,002,806 proposes the connection ofthe rotor by means of a rod with spherical joints, with a leverconnected to one of the pins of the chute. Other tilting mechanisms arealso known from WO95/21072, U.S. Pat. No. 4,368,813, U.S. Pat. No.3,814,403 and U.S. Pat. No. 3,766,868.

[0028] Reference symbol 50 refers to a first casing mounted on thesupport frame 12. This casing 50 contains a vertical shaft 54, called arotation shaft 54 hereafter, which is connected through a angular geartransmission mechanism 52 to a horizontal output shaft 56. The upper endof the rotary shaft 54 is coupled via a mechanical reducer 58 with anelectric motor 60. The lower end of the rotary shaft 54 sealably emergesout through the base plate of the casing 50 and is provided with apinion 62 which engages with a toothed crown 64 of the suspension rotor18. It remains to be noted that the support frame 12 is provided with aport 66 for the passage of the pinion 62, which is sealably closed bythe base plate of the casing 50. Reference symbol 70 refers to a secondcasing mounted on the support frame 12. This casing 70 contains avertical shaft 74, hereafter called the tilt controlling shaft 74 whichis connected by a angular gear transmission mechanism 72 to a horizontalinput shaft 76. The upper end of the rotary shaft 74 is coupled via amechanical reducer 78 with an electric motor 80. The lower end of thetilt controlling shaft 74 sealably emerges out through the base plate ofthe casing 70 and is provided with a pinion 82 which engages with atoothed crown 84 of the control rotor 26. It remains to be noted thatthe support frame 12 is also provided with a port 86 for the passage ofthe pinion 82, which is sealably closed by the base plate of the casing70. The horizontal output shaft 56 of the casing 50 and the horizontalinput shaft 76 of the casing 70 are coupled with each other by means ofa clutch 90. When the clutch 90 is in the engaged position, both rotors18, 28 are interdependent in rotation, i.e. it is impossible toaccelerate or decelerate one of the rotors 18, 28 relatively to theother. Further, the different gear ratios are dimensioned in such a waythat the speeds of rotation of both rotors 18, 28 are strictly identicalin this case. In order to accelerate or decelerate one of the rotors 18,28 with respect to the other, the clutch must therefore be disengaged90.

[0029] The reference symbol 100 globally refers to a control systemcontrolling the device for distributing bulk materials 10. This controlsystem 100 comprises a control central unit 102 comprising for example aprogrammable controller, which controls the electric motor 60 via afirst variable speed drive 104 and the electric motor 80 via a secondvariable speed drive 106. As feedback signals, the control central unit102 receives signals from two angle sensors 108 and 110. The anglesensor 108 senses via a gear 112 the angular position of the rotaryshaft 54 consequently that of the tilt controlling rotor 28. By means ofthe signal from the angle sensor 108, the central unit 102 computes theinstantaneous speed of rotation of the chute 32, as well as itsposition. On the; basis of the signal from both angle sensors 108 and110, the central unit 102 computes the inclination of the chute and theinstantaneous tilting speed of the chute 32. A set point unit 116enables set values to be entered into the control central unit 102 asregards notably the speed of rotation, the inclination and the tiltingspeed of the chute 32.

[0030] The operation of the device for distributing bulk materials 10will now be described in more detail.

[0031] First of all, let us assume that the chute 32 is balanced so thatit is capable of tilting under the effect of it own weight in aquasi-vertical position (i.e. in a position at which its angle ofinclination, as measured with respect to the vertical, is minimal), andthat the tilting mechanism is dimensioned so that it is capable ofrespectively accelerating the tilt controlling rotor in the direction ofthe arrow 120 and the suspension rotor in the direction of the arrow120′, when the chute 32 returns under the effect of its own weight to aposition of minimal inclination this notably means that a moment must beapplied to the tilt controlling rotor 28 in order to maintain the latterin equilibrium for a given angle of inclination. Let us also assume thatthe chute 32 should be rotated at speed N in the direction of the arrow120. To increase the angle of inclination of the chute 32 as measuredwith respect to the vertical, the variable speed drive 10106 has theelectric motor 80 operate as a generator which imposes a braking momentto the tilt controlling rotor 28, whereas the motor 60 drives thesuspension rotor 18 at speed N in the direction of the arrow 120.Indeed, if the braking moment exerted by tilt controlling rotor becomesgreater than the moment required for maintaining the chute in theequilibrium position, the tilt controlling rotor 28 decelerates withrespect to the suspension rotor and the angle of inclination of thechute 32 as measured with respect to the vertical, increases. The morethe braking moment exerted by the tilt controlling rotor 28 exceeds theequilibrium moment of the chute 32, the higher the deceleration of thetilt controlling rotor 28 with respect to the suspension rotor 18 andthe faster the tilting speed of the chute 32. Of course, it is motor 60which drives the suspension rotor 18, which must provide the requiredpower for overcoming the braking moment applied on the tilt controllingrotor 28 in order to decelerate the latter. This power is partlycompensated by the electrical power which the variable speed drive 10,106 injects into the mains electrical power supply network, when themotor 80 operates as a generator for generating the braking moment ofthe tilt controlling rotor 28. If the intention is to maintain the chute32 in rotation at speed N in the direction of the arrow 120 with aconstant angle of inclination, the braking moment of the motor 80 mustbe set by means of the variable speed drive 106 so that the speed ofrotation of the tilt controlling rotor 28 is substantially identical tothe speed of rotation N of the suspension rotor 18. When the speeds ofrotation of both rotors 18, 28 are quasi identical, the clutch 90 isengaged. From this moment, both rotors 18, 28 are interdependent inrotation and rotate at the same speed. The angle of inclination of thechute 32 is frozen at its value at the time of the engagement. Motor 80has no longer to develop a braking torque, it is capable of consequentlyrotate idly. As a result the motor 60 does no longer need to overcomethe braking moment of the tilt controlling rotor 28, which means thatits absorbed power is considerably reduced. To reduce once again theinclination of the chute 32 with respect to the vertical, the clutch 90is simply disengaged. The tilt controlling rotor 28 undergoes, by aparticular balance of the chute 32, an acceleration in the directions ofthe arrow 120, which reduces the delay of the tilt controlling rotor 28relatively to the suspension rotor 18. As a result, the angle ofinclination of the chute 32 with respect to the vertical, is againreduced. To control the tilting speed of the chute 32 towards itsposition of minimal angle of inclination, the control central unit 102may operate the electric motor 80 via the variable speed drive 106 as agenerator, which imposes a braking moment to the tilt controlling rotor.This braking moment should of course, remain smaller than the momentrequired for maintaining the chute 32 in its equilibrium position. Nowlet us assume that the chute 32 should rotate at speed N in the oppositedirection, i.e. in the direction of the arrow 120′. In order to increasethe angle of inclination of the chute 32 as measured with respect to thevertical, the variable speed drive 106 operates the electric motor 80 sothat it drives the tilt controlling rotor 28 at a speed N′>N in thedirection of the arrow 120′, and the variable speed drive 104 operatesthe electric motor 60 as a generator, which imposes a braking moment tothe suspension rotor 18. By means of the variable speed drive 106, thecontrol unit 102 controls the driving speed N′ of the tilt controllingrotor 28, in order to adjust the tilting speed of the chute 32 to thedesired value. By means of the variable speed drive 104, the controlunit 102 controls the motor 60 so that the speed of rotation of thesuspension rotor 18 remains substantially equal to the desired value N.Now, it is the motor 80 which must provide the power required forovercoming the braking moment applied to the suspension rotor 18 inorder to maintain the latter at the speed of rotation N. This power ispartly compensated by the electrical power that the variable speed drive104 injects into the mains electrical supply network, when motor 60operates as a generator for generating the braking moment of thesuspension rotor 18. If the intention is to maintain the chute 32rotating at speed N, in the direction of the arrow 120′, with a constantangle of inclination, the braking moment of the tilt rotor 28 should beset by means of the variable speed drive 106 until a zero tilting speedis obtained. A this moment, the speed of rotation of the tiltcontrolling rotor 28 is the same as the speed of rotation N of thesuspension rotor 18 and clutch 90 is engaged. Both rotors 18, 28 are nowinterdependent in rotation and rotate at the same speed. Motor 60 has noneed to develop a braking torque; it is capable of rotating idly. As aresult, motor 80 has no longer to overcome the braking moment of thesuspension rotor 18 which means that its absorbed power is considerablyreduced. It remains to be noted that if clutch 90 is engaged, the motor60 can be also used for driving the chute into rotation in the directionof the arrow 120′ at speed N. To again reduce the inclination of thechute 32 with respect to the vertical, clutch 90 is first disengaged.The suspension rotor 18 is subject, by the particular balance of thechute 32, to a driving moment in the directions of the arrow 120′, whichtends to accelerate it in the direction of rotation. By means of thevariable speed drive 104, the control unit 102 sets the braking momentof the suspension rotor 18 to adjust the speed of rotation of the chute32 to the desired value N. By means of the variable speed drive 106, thecontrol unit 102 sets the driving moment of the tilt controlling rotor28 in order to adjust the tilt speed of the chute 32 to the desiredvalue. If the speed of rotation N′ of the tilt controlling rotor 28 isless than the speed of rotation N of the suspension rotor 18, then theangle of inclination of the chute 32 with respect to the vertical isreduced.

[0032] If it is not required to drive the chute 32 into rotation in thedirection of the arrow 120′, the “motor 80” should only fulfill thefunction of a brake capable of exerting a braking moment on the tiltcontrolling rotor 28. In this event, of course, the motor 80 itsinverter 106 can be replaced with a mechanical, hydraulic, magnetic orelectromagnetic braking device, equipped with a suitable control devicefor controlling the variation of the angle of inclination of the chute32 by controlled braking of the tilt controlling rotor 28. It is thenpossible to do without the variable speed drive which powers the motor,provided that the latter is able to deliver a substantially constantspeed of rotation when it has to overcome a variable braking torque.

[0033] It remains to be noted that instead of balancing the chute sothat it tilts under the effect of its own weight into a position atwhich its angle of inclination as measured with respect to the vertical,is minimal, it might be also balanced so that it tilts under the effectof a counterweight into a position at which its angle of inclination, asmeasured with respect to the vertical, is maximal. Finally, forbalancing the chute so that it returns into a position at which itsangle of inclination with respect to the vertical is either maximal orminimal, it is also possible to resort to springs or hydraulic cylinderscapable of storing potential energy when the chute is tilted in onedirection and of releasing it when the chute must be tilted in thereverse direction.

[0034] Let us now assume that the tilting mechanism is self-blocking,i.e. that no moment needs to be applied to the tilting control motor inorder to maintain the angle of inclination of the chute constant. Againlet us assume that the chute 32 should be rotated at speed N in thesense of the arrow 120. To increase the angle of inclination of thechute 32 as measured with respect to the vertical, the variable speeddrive 106 operates the electrical motor 80 as a generator, which imposesa braking moment to the tilt controlling rotor 28, whereas motor 60drives the suspension rotor 18 at speed N in the direction of the arrow120. Indeed, if the braking moment exerted on the tilt controlling rotorbecomes larger than a certain value, the tilt controlling rotor 28decelerates relatively to the suspension rotor 18 and the angle ofinclination of the chute 32 as measured with respect to the vertical,increases. The larger the deceleration of the tilt controlling rotor 28with respect to the suspension rotor 18, the higher the tilting speed ofthe chute 32. Of course, it is motor 60 which must provide the powerrequired for overcoming the braking moment applied to the tiltcontrolling rotor 28 in order to decelerate the latter. This power ispartly compensated by the electrical power that the variable speed drive106 injects into the mains electrical power supply network, when motor80 operates as a generator for producing the braking moment of the tiltcontrolling rotor 28. To keep the chute 32 rotating at speed N in thedirection of the arrow 120 with a constant angle of inclination, it issufficient to operate the motor 80 under no load. However, if thetilting mechanism is not perfectly self-blocking for all the angles ofinclinations of the chute, it is then recommended to engage the clutch90 nonetheless, in order to provide a strictly constant angle ofinclination for the chute 32. To reduce the inclination of the chute 32with respect to the vertical, the variable speed drive 106 operates theelectric motor 80 so that it drives the tilt controlling rotor 28 at aspeed N′>N in the direction of the arrow 120, and the variable speeddrive 104 operates the electric motor 60 as a generator, which imposes abraking moment to the suspension rotor 18. By means of a variable speeddrive 104, the control unit 102 sets the braking moment of thesuspension rotor 18 in order to adjust the speed of rotation of thechute 32 to the desired value N. By means of the variable speed drive106, the control unit 102 sets the speed of rotation N′ of the tiltingrotor 28 in order to adjust the tilting speed of the chute 32 to thedesired value. Let us now assume that the tilting mechanism isself-blocking and that the chute 32 needs to be rotated at speed N inthe direction of the arrow 120′. To increase the inclination of thechute 32 with respect to the vertical, the variable speed drive 106operates the electric motor 80 so that it drives the tilt controllingrotor 28 at a speed N′>N in the direction of the arrow 120′, and thevariable speed drive 104 operates the electric motor 60 as a generatorwhich imposes a braking moment to the suspension rotor 18. By means ofthe variable speed drive 104, the control unit 102 sets the brakingmoment of the suspension rotor 18 in order to adjust the speed ofrotation of the chute 32 to the desired value N. By means of thevariable speed drive 106, the control unit 102 sets the tilting speed ofthe chute 3. In order to reduce the tilt of the chute 32 with respect tothe vertical, the variable speed drive 104 operates the electric motor60 so that it drives the suspension rotor 18 at speed N in the directionof the arrow 120′, and the variable speed drive 106 operates theelectric motor 80 as a generator which imposes a braking moment to thetilt controlling rotor 28. By means of the variable speed drive 106, thecontrol unit 102 sets the braking moment of the tilt controlling rotor28 in order to adjust the tilting speed of the chute 32 to the desiredvalue. By means of the variable speed drive 104, the control unit 102sets the speed of rotation of the suspension rotor 18 to the value N.

[0035] Upon its assembly or during maintenance work, the angle sensor110 must be reset, i.e. an initial count value must be associated with awell-defined angle of inclination of the chute 32. With reference toFIG. 3, it is seen that the suspension mechanism 36′ is equipped with anangle abutment 120 and with a lever 122 interdependent with thesuspension pin 40′. To reset the angle sensor 110, the tilt rotor 28 isdriven by means of motor 80 in order to have the lever 122 abut againstthe angle abutment 120.

[0036] In the embodiment of FIG. 4, a differential angle sensor 126 isused which directly senses the angular position relatively to bothrotors 18 and 28. This differential angle sensor 126 is mounted inparallel on the clutch 90. If the device does not comprise a clutch 90because the tilting mechanism of the chute is perfectly self-blocking,then the differential angle sensor 126 may take the place of the clutch90, so as to be directly connected between both shafts 56 and 76.Considering that the casing of the differential angle sensor 126 is alsorotating, a wireless transmission of measurements towards a receiver 128which is rotationally fixed, is provided advantageously.

[0037] In the embodiment of FIG. 5, a differential measurement mechanism130 is used, which is connected in parallel on the clutch 90. Thismechanism comprises a first input shaft 132, a second input shaft 134and an output shaft 136. The first input shaft is rotated by the outputshaft 56 of the casing 50. It consequently senses the angular positionof the suspension rotor 18. The second input shaft is rotated by theinput shaft 76 of the casing 70. It consequently senses the angularposition of the tilt controlling rotor 28. This differential measurementmechanism 130 additionally comprises a system of planetary gearsdimensioned in order that the output shaft 136 is rotationally fixedwhen both rotors 18, 28 have the same speed of rotation, so that itreproduces the angle of inclination of the chute 32 in a rotationallyfixed reference system.

[0038]FIG. 6 shows a planar view of this planetary gear system. Ahorizontal annular toothed wheel 138 is seen, which engages on itsexternal perimeter with a pinion 140 of the first input shaft 132; asolar wheel 142 which is borne by the second input shaft 134; twosatellite pinions 144 which engage with the internal perimeter of theannular toothed wheel 138 and the solar wheel 142; and a satellitepinion support 146, with which is coupled the output shaft 136. A singleangular sensor 148 then senses the angular position of the output shaft136 and thereby detects the tilt of the chute in a rotationally fixedreference system.

1. A device for distributing bulk materials comprising: a support frame(12); a distribution chute for the bulk materials; a suspension rotor(18) mounted in said support frame (12) so as to be capable of rotatingabout a substantially vertical axis of rotation, said chute (32) beingsuspended to said suspension rotor (18) so as to be tiltable about asubstantially horizontal tilt axis; a first motor (60) capable ofrotating said suspension rotor (18) about its axis of rotation in afirst direction; a tilt controlling rotor (28) mounted in said supportframe (12) so that it is capable of rotating about a substantiallyvertical axis of rotation; and a tilting mechanism (36, 36′) connectedbetween said chute (32) and said tilt controlling rotor (28), saidtilting mechanism (36, 36′) being designed in order to transform adifferential rotation of said suspension rotor (18) and of said tiltcontrolling rotor (28) into a variation of the angle of inclination ofsaid chute (32) between two extreme positions; characterized in thatsaid chute (32) is balanced so that it returns to a first of its twoextreme positions, while accelerating said tilt controlling rotor (28)via said tilting mechanism (36, 36′) in the direction of rotation ofsaid suspension rotor (18); a first braking device (80) is associatedwith said tilt controlling rotor (28) so that it is capable of exertinga braking moment on said tilt controlling rotor (28); and a firstcontrol device (102, 106) is associated with said first braking device(80) in order to control the variation of the angle of inclination ofsaid chute (32) by controlled braking of said tilt controlling rotor(28).
 2. The device according to claim 1, characterized by: atransmission mechanism (52, 56, 72, 76) with a clutch (90) which isconnected between said suspension rotor (18) and said tilt controllingrotor (28), so that in the engaged position of said clutch (90), saidmechanism makes both rotors (18, 28) interdependent in rotation whileproviding equal speeds of rotation for both rotors (18, 28).
 3. Thedevice according to claim 1 or 2, characterized by: a second motor (80)which is associated with said tilt controlling rotor (28) so that it iscapable of driving the latter about its axis of rotation in a seconddirection of rotation, opposite to said first direction of rotation; asecond braking device (60) which is associated with said suspensionrotor (18) so that it is capable of exerting a braking moment on saidsuspension rotor (18).
 4. The device according to claim 3, characterizedby: a second control device (102, 104) which is associated with saidsecond braking device (60), so as to control the variation of the angleof inclination of said chute (32) rotating in said second direction byvarying the braking moment of said suspension rotor (18).
 5. The deviceaccording to claim 4, characterized by: a variable speed drive (106)associated with said second motor (80); and a control device associatedwith said variable speed drive (106) in order to control the speed ofrotation of said suspension rotor (18), by varying the speed of rotationof said tilt controlling rotor (28).
 6. The device according to claim 3,characterized by: a variable speed drive (106) associated with saidsecond motor (80); and a control device associated with said variablespeed drive (106) in order to control the speed of tilting of said chuteby varying the speed of rotation of said tilt controlling rotor (28)with the speed of rotation of said suspension rotor (18) being keptconstant.
 7. The device according to any of claims 3 to 6, characterizedin that said first motor (60) and said second braking device (80), saidsecond motor (80) and said first braking device (60), respectively, forma unit comprising a rotating electric machine powered by an electricalcircuit so that it is capable of operating in motor mode, developing adriving torque, and in generator mode, developing a braking torque in atleast one direction of rotation.
 8. The device according to claim 7,characterized in that said electric rotating machine is an electricmotor (60, 80) equipped with a speed reducer (58, 78), and in that saidelectric circuit is a static frequency converter (104, 106).
 9. Thedevice according to any of claims 1 to 8, characterized in that saidfirst control device (102, 106), said second control device,respectively, comprises: a first angle sensor (108) sensing the angularposition of said suspension rotor (18); a second angle sensor (110)sensing the angular position of said tilt controlling rotor (28); andcomputation means (102) for computing the relative angular position ofboth rotors (18, 28).
 10. The device according to any of claims 1 to 8,characterized in that said first control device (102, 106), said secondcontrol device, respectively, comprises: a differential angle sensor(126) sensing the angular position of both rotors (18, 28).
 11. Thedevice according to any of claims 1 to 8, characterized in that saidfirst control device (102, 106) said second control device (102, 104),respectively, comprises: a differential measurement mechanism (130),with a first input shaft (132), a second input shaft and an output shaft(136), said first input shaft (132) being rotated by said suspensionrotor (18), said second input shaft (134) being rotated by said tiltcontrolling rotor (28), and said differential measurement mechanism(130) being dimensioned so that said output shaft (136) is rotationallyfixed when both rotors (18, 28) have the same speed of rotation; and anangle sensor (148) sensing the angular position of said output shaft(136).
 12. A device for distributing bulk materials comprising: asupport frame (12); a distribution chute for the bulks materials; asuspension rotor (18) mounted in said support frame (12) so that it iscapable of rotating about a substantially vertical axis of rotation,said chute (32) being suspended to said suspension rotor (18) so as tobe tiltable about a substantially horizontal tilt axis; a first motor(60) able to drive the suspension rotor (18) into rotation about itsaxis in a first direction; a tilt controlling rotor (28) mounted in saidsupport frame (12) so that it is capable of rotating about asubstantially vertical axis of rotation; and a tilting mechanism (36,36′) connected between said chute (32) and said tilt controlling rotor(28), said tilting mechanism (36, 36′) being designed in order totransform a differential rotation of said suspension rotor (18) and ofsaid tilt controlling rotor (28) into a variation of the angle ofinclination of said chute (32) between two extreme positions;characterized in that a first braking device (80) is associated withsaid tilt controlling rotor (28) so that it is capable of exerting abraking moment on said tilt controlling rotor (28); a second motor (80)is associated with said tilt controlling rotor (28) so that it iscapable of driving the latter about its axis in said first direction ata higher speed of rotation than the desired speed of rotation for saidchute (32); a second braking device (60) is associated with saidsuspension rotor (18), so that it is capable of exerting a brakingmoment on said suspension rotor; and a control device (102, 104, 106)able to control the tilting of said chute (32) in a first direction bydriving said suspension rotor (18) in said first direction and bycontrolled braking of said tilt controlling rotor (28) by means of saidfirst braking device (80), and in a second direction, by driving saidtilt controlling rotor (28) in said first direction at a higher speed ofrotation than the desired speed of rotation for said chute (32) and bycontrolled braking of said suspension rotor (18) by means of said secondbraking device (60).
 13. The device according to claim 12, characterizedin that said tilting mechanism (36, 36′) is a self-blocking mechanism.14. The device according to claim 12, characterized by a transmissionmechanism (52, 56, 72, 76) with a clutch (90) which is connected betweensaid suspension rotor (18) and said tilt controlling rotor (28), so thatin the engaged position of said clutch (90), said mechanism makes bothrotors (18, 28) interdependent in rotation by providing equal speeds ofrotation for both rotors (18,28).
 15. The device according to any ofclaims 12 to 14, characterized in that: said first motor (60) is able todrive said suspension rotor (18) in a second direction of rotationopposite to said first direction of rotation, at the desired speed ofrotation for said chute (32); and said second motor (80) is able todrive said tilt controlling rotor (28) in a second direction ofrotation, at a higher speed of rotation than the desired speed ofrotation for said chute (32).
 16. The device according to claim 13,characterized in that, upon a rotation of said chute (32) in said seconddirection, said control device associated with said first braking device(80), with said second braking device (60) and with said second motor(80), is able to control the tilting of said chute (32): in a firstdirection, by driving said tilt controlling rotor (28) by means of saidsecond motor (80) in said second direction, with a higher speed ofrotation than the desired speed of rotation for said chute (32) and bycontrolled braking of said suspension rotor (18) by means of said secondbraking device (60); and in a second direction, by driving saidsuspension rotor (18) in said second direction and a controlled brakingof said tilt controlling rotor (28) by means of said first brakingdevice (80).
 17. The device according to any of claims 12 to 16,characterized in that: a variable speed drive (106) is associated withsaid second motor (80); and said control device is able to control saidvariable speed drive (106) in order to control the speed of rotation ofsaid suspension rotor (18), by varying the speed of rotation of saidtilt controlling rotor (28).
 18. The device according to any of claims12 to 16, characterized in that: a variable speed drive (106) isassociated with said second motor (80); and said control device is ableto control said variable speed drive (106) in order to control thetilting speed of said chute (32) by varying the speed of rotation ofsaid tilt controlling rotor (28).
 19. The device according to any ofclaims 12 to 18, characterized in that, said first motor (60) and saidsecond braking device (60), said second motor (80) and said firstbraking device (80) respectively, form a unit comprising a rotatingelectric machine powered by an electrical circuit so that it is capableof operate in motor mode, developing a driving torque, and in generatormode developing a braking torque, in at least one direction of rotation.20. The device according to claim 19, characterized in that, saidrotating electric machine is an electric motor (60, 80) equipped with aspeed reducer (58, 78), and in that said electrical circuit is a staticfrequency converter (104, 106) allowing operation of said rotatingelectric machine in the four quadrants of the speed ofrotation/developed torque diagram.
 21. The device according to any ofclaims 12 to 20, characterized in that said control device comprises: afirst angle sensor (108) sensing the angular position of said suspensionrotor (18); a second angle sensor (110) sensing the angular position ofsaid tilt controlling rotor (28); and computation means (102) forcomputing the relative angular position of both rotors (18, 28).
 22. Thedevice according to any of claims 12 to 21, characterized in that saidcontrol device comprises: a differential angle sensor (126) sensing therelative angular position of both rotors (18, 28).
 23. The deviceaccording to any of claims 12 to 21, characterized in that said controldevice comprises: a differential measurement mechanism (130) with afirst input shaft (132), a second input shaft (134) and an output shaft(136), said first input shaft (132) being rotated by said suspensionrotor (18), said second input shaft (134) being rotated by said tiltcontrolling rotor (28), and said differential measurement mechanism(130) being dimensioned so that said output shaft (136) is rotationallyfixed when both rotors (18, 28) have the same speed of rotation; and anangle sensor (148) sensing the angular position of said output shaft(136).
 24. The device according to any of claims 12 to 21, characterizedin that said control device comprises: an inclination sensor for saidchute (32) rotating with said chute (32), a transmitter associated withsaid inclination sensor and at least one receiver mounted fixedly inrotation in said support frame (12).